664
FXUS63 KILX 291105
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
605 AM CDT Mon Apr 29 2024

.KEY MESSAGES...

- Showers and a few thunderstorms will push eastward toward the
  Indiana border by dawn, and diminish west of I-57 during this
  morning. Chances of showers and isolated thunderstorms continues
  this afternoon and into the evening in eastern IL. The severe
  potential has greatly decreased, though heavy rains and
  localized flooding remains risks early this morning.

- Above normal temperatures will prevail for the remainder of the
  week. Fair weather is expected Tuesday. Periodic chances of
  showers and thunderstorms will then occur Tue night through
  Friday.

&&

.DISCUSSION...
Issued at 400 AM CDT Mon Apr 29 2024

A large area of showers and a few embedded thunderstorms was
moving east over central IL early this morning, as was as far east
as I-57 where thunderstorms were present by 330 am. Showers were
diminishing west of the IL river. MRMS was showing rainfall
estimates as high as a half to 1 inch from highway 51 west with
this convection. Heavier pockets of rainfall over 1 inch estimated
from Jacksonville and sw of Litchfield southwest into portions of
central and southwest MO. This convection is supported by a 35-50
kt SSW low level jet over eastern and southern IL, with strongest
winds going into southeast IL. PW values of 1.2-1.5 inches
assisting with moderate to heavier rainfall rates and WPC has
marginal risk of excessive rainfall over much of area early this
morning.

Predawn surface map shows 1003 mb low pressure over sw MN with its
cold front through eastern Iowa, central MO. Temps had cooled into
the upper 50s to near 60F with the rain showers from highway 51
west while milder temps 65-70F in east central and southeast IL.

Latest CAMs shift the convection eastward to the Indiana border by
sunrise and continues to diminish eastward from the IL river
toward I-57 during this morning. Total rainfall amounts of a half
to 1 inch expected with local 1-2 inch amounts possible and could
lead to localized flooding due to a saturated ground from recent
heavy rainfall past few days. Lincoln is up to 5.86 inches of rain
so far this month through 1 am and is just 0.02 inches from the
10th wettest April. Cold front to slowly push eastward into
central IL by early afternoon and through southeast IL by early
overnight. Will continue to see good chances of showers and
isolated thunderstorms in eastern IL this afternoon and lingering
in southeast IL into mid evening. Highs today in the lower 70s
with breezy sw winds gusting 20-25 mph. Lows overnight range from
around 50F from I-72 north to the mid to upper 50s southeast of
I-70.

Some lingering clouds in southeast IL Tue morning, otherwise a
fair amount of sunshine expected over the area Tuesday as weak
high pressure 1016 mb moves over IL. Lighter winds expected with
nearby high pressure ridge and comfortable temperatures and
humidity levels. Highs Tue in the mid to upper 70s and dewpoints
in the 50s.

A short wave trof near the Pacific Northwest coast to track
eastward into the upper MS river valley during Tue night and bring
next chance of showers and thunderstorms to central IL overnight Tue
night while southeast IL stays dry. Some upper level ridging into
IL on Wed to keep most areas dry that day, though isolated
convection possible over the IL river valley later Wed afternoon
and evening. Warm highs Wed in the upper 70s and lower 80s with
partly sunny skies.

Deepening mid/upper level trof over the Rockies during mid week
helps eject a wx system from the Central High Plains Wed afternoon
ne toward the upper Midwest Thu night and bringing a cold front
eastward through IL overnight Thu night into Fri morning.
Convection chances to increase from the west later Thu and Thu
night and then diminish from the west after frontal passage on
Friday. Breezy south winds gusting 25-35 mph on Thu brings warm
highs in the low to mid 80s along with moist dewpoints in the low
to mid 60s. Could be a risk of strong to possibly severe storms
later Thu afternoon into Thu night though SPC does not have an
outlooked area yet. WPC has marginal to slight risk of excessive
rainfall for Thu night over IL with the higher risk (slight risk)
west of the IL river. Highs Fri and Saturday mostly in the lower
70s, near 75F at Lawrenceville. Drier weather looks to return
overnight Fri night into Saturday night. Some signals to chances
of showers and thunderstorms next Sunday though models not in very
good agreement that far out.

The Climate Prediction Center (CPC) 8-14 Day outlook for May
6-12th has 50-60% chance of above normal temperatures over central
and southeast IL, while precipitation trending near or slightly
above normal.

07

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 550 AM CDT Mon Apr 29 2024

Large band of showers and isolated thunderstorms along and east of
highway 51 at sunrise, will diminish at BMI and DEC between 12-13Z
and CMI by 13-14Z. MVFR vsbys possible with heavier rain showers
especially at CMI next hour or so. Otherwise will see MVFR
ceilings become more common behind the rain band during this
morning and lifting to VFR during the afternoon. Though ceilings
will be variable today. Low clouds scatter out during mid/late
afternoon from the west with fair skies tonight. Variable winds
at dawn to become south to SSW at 10-15 kts with gusts 18-24 kts
later this morning. Wind veer SW and possibly west this evening
and diminish to 4-8 kts after sunset.

07

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$